import java.util.Set;
import java.util.TreeSet;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 86183
 * Date: 2024-02-28
 * Time: 16:50
 */
public class Test {
    public static void main(String[] args) {
        Set<String> set=new TreeSet<>();
        set.add("a");
        set.add("bc");
        set.add("bcr");
        System.out.println(set.size());
        System.out.println(set);
        System.out.println("==================");
        set.add("a");
        System.out.println(set);
        for (String x: set) {
            System.out.println(x);
        }
        System.out.println("===================");
        //set.clear();
        System.out.println(set.size());
        System.out.println("========================");
        System.out.println(set.contains("a"));
        System.out.println(set.remove("a"));
        System.out.println(set.size());
        System.out.println(set.remove("d"));
      System.out.println(set.remove(null));



    }
}
